Visitors can request an invite. We did, and Google asked us what kind of device we used—offering a choice of iPhone, Android, or "other."

That suggests that Google is getting away from its earlier dependence on special hardware on Android phones and is looking to broaden Wallet's acceptance among consumers and merchants.

While Google ran a lot of ads on buses and billboards for Wallet, the mobile-payments service never appeared to take off with consumers—in part because it was limited to specific phones carried by Sprint and Virgin Mobile and relied on NFC, or near-field communications, a short-range wireless technology.

Google also offers a Web-based version of Wallet for online payments, including purchases of digital content and apps in the Google Play store. It has offered a similar service for years, previously under the name Google Checkout.

Osama Bedier, a former PayPal executive who now heads up Google's payments efforts, is speaking today at the Money2020 conference in Las Vegas, but he's not expected to unveil details of the new product today, a source tells us.